Vehicle battery pack

ABSTRACT

A vehicle battery pack capable of suppressing a variation in cooling performance for a battery module by a cooling pipe. A vehicle battery pack includes a cooling pipe in a flat plate shape that abuts a lower surface of respective one of battery modules; and an elastic urging member that urges the cooling pipe upward to make the cooling pipe abut the lower surface of respective one of the battery modules. The elastic urging member has plural elastically-deformable legs that are aligned in a longitudinal direction of the cooling pipe.

TECHNICAL FIELD

The present disclosure relates to a vehicle battery pack that includes acooling mechanism for cooling a battery module.

BACKGROUND ART

Conventionally, a battery module is mounted on an electric vehicle, ahybrid vehicle, and the like. A temperature of the battery module islikely to be increased in a use state during travel of the electricvehicle, and the like. Thus, the battery module has to be cooled to anappropriate temperature for use of the battery module.

To handle the above problem, as disclosed in JP-A-2013-69690, theconventional vehicle such as the electric vehicle includes a coolingsystem that includes a cooling pipe in contact with a lower surface ofthe battery module. This cooling system includes a spring sheetfunctioning as a plate spring that makes the cooling pipe abut the lowersurface of the battery module. The spring sheet has an abutment portionthat abuts the cooling pipe; and an elastically-deformable arm portion.The abutment portion is pressed against the cooling pipe by an urgingforce that is generated by elastic deformation of the arm portion. Theabutment portion and the arm portion continuously extend along alongitudinal direction of the cooling pipe. The arm portion urges anentire length of the abutment portion to the cooling pipe.

SUMMARY

In the above cooling system, the spring sheet is used to make thecooling pipe abut the lower surface of the battery module, and thisspring sheet has the arm portion that continuously extends along thelongitudinal direction of the cooling pipe. In such a spring sheet, theurging force for urging the cooling pipe to the lower surface of thebattery module possibly fluctuates according to the temperature of thebattery module in the use state. For example, the arm portion issoftened in a high-temperature time of the battery module. On thecontrary, the arm portion is hardened in a low-temperature time thereof.Accordingly, a variation in the urging force for urging the cooling pipeto the lower surface of the battery module is significant. As a result,cooling performance for the battery module by the cooling pipe varies.

The present disclosure has been made in view of the above circumstanceand therefore provides a vehicle battery pack capable of suppressing avariation in cooling performance for a battery module by a cooling pipe.

The vehicle battery pack according to the present disclosure is avehicle battery pack that includes a battery module; a cooling pipe in aflat plate shape that abuts a surface of the battery module; and anurging member that urges the cooling pipe in a direction to abut thesurface of the battery module. The urging member has pluralelastically-deformable legs that are aligned in a longitudinal directionof the cooling pipe.

According to such a configuration, since the urging member has theplural elastically-deformable legs that are aligned in the longitudinaldirection of the cooling pipe, it is possible to urge the cooling pipeto the surface of the battery module by each of the legs. In this way,it is possible to suppress a variation in an urging force received bythe cooling pipe between a high-temperature time and a low-temperaturetime. As a result, in a state of receiving the urging force, thevariation in which is suppressed (that is, a state where a variation inthermal contact resistance is suppressed), the cooling pipe abuts thesurface of the battery module, and thus it is possible to suppress avariation in cooling performance for the battery module by the coolingpipe.

In the above vehicle battery pack, preferably, the surface of thebattery module is a lower surface of the battery module.

According to such a configuration, it is possible to urge the coolingpipe to the lower surface of the battery module by each of the legs ofthe urging member. In this configuration, the battery module is placedon the cooling pipe, and thus the urging member can receive weight ofthe battery module via the cooling pipe. As a result, the urging memberis elastically deformed by using the weight of the battery module andcan urge the cooling pipe to the lower surface of the battery module byusing a restoring force of the urging member. Therefore, with a simplestructure that the battery module, the cooling pipe, and the urgingmember are stacked and arranged in a vertical direction, it is possibleto suppress the variation in the urging force received by the coolingpipe and to suppress the variation in the cooling performance for thebattery module by the cooling pipe.

In the above vehicle battery pack, preferably, a tip of each of the legshas a curved surface shape.

According to such a configuration, since the tip of each of the legs hasthe curved surface shape, each of the legs can smoothly and elasticallybe deformed when each of the legs abuts an abutment surface of a casefor the battery pack, or the like. As a result, an impact of a variationin the tip shape of the legs becomes small, and thus the cooling pipecan reliably be urged to the battery module.

In the above vehicle battery pack, preferably, each of the legs has ahollow shape.

According to such a configuration, since each of the legs has the hollowshape, each of the legs can smoothly and easily be deformed elasticallywhen each of the legs abuts the abutment surface of the case for thebattery pack, or the like. As a result, even in the case where anattachment error of the cooling pipe or the battery module occurs, suchan error can reliably be absorbed by elastic deformation of the legs,and thus it is possible to further reliably urge the cooling pipe to thebattery module.

In the above vehicle battery pack, preferably, each of the legs has atapered shape.

According to such a configuration, since each of the legs has thetapered shape, each of the legs can smoothly and elastically be deformedwhen each of the legs abuts the abutment surface of the case for thebattery pack, or the like. As a result, the impact of the variation inthe tip shape of the legs becomes small, and thus the cooling pipe canreliably be urged to the battery module.

In the above vehicle battery pack, preferably, the urging member isconfigured to be divided into plural pieces.

According to such a configuration, it is possible to improveproductivity of the urging member.

In the above vehicle battery pack, preferably, the battery module hasplural sheets of battery cells, the number of the legs is the same asthe number of the battery cells, the plural legs are arranged inalignment in an alignment direction of the plural sheets of the batterycells, and each of the legs is arranged at a position capable ofapplying an urging force to respective one of the battery cells.

According to such a configuration, the plural legs of the urging membercan apply the uniform urging force to the plural sheets of the batterycells in the battery module.

Preferably, the above vehicle battery pack further includes a holdingmember that is arranged between the cooling pipe and the urging memberand holds the urging member on the cooling pipe.

According to such a configuration, since the holding member holds thecooling pipe at a position between the cooling pipe and the urgingmember, it is possible to improve a holding property for the coolingpipe. As a result, the urging member applies the uniform urging force tothe cooling pipe, and thus the battery module can be cooled evenly bythe cooling pipe.

Preferably, the above vehicle battery pack further includes a heaterthat heats the battery module, and the holding member holds the heaterat a position capable of heating the battery module.

According to such a configuration, since the holding member holds theheater at the position capable of heating the battery module, it ispossible to reliably heat the battery module evenly.

According to the vehicle battery pack in the present disclosure, it ispossible to suppress the variation in the cooling performance for thebattery module by the cooling pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a basic configuration of a vehiclethat includes a battery pack according to an embodiment of the presentdisclosure;

FIG. 2 is an exploded perspective view of the battery pack in FIG. 1;

FIG. 3 is an exploded perspective view of a cooling mechanism in FIG. 2;

FIG. 4 is a perspective explanatory view illustrating a flow of arefrigerant in the cooling mechanism in FIG. 3;

FIG. 5 is a perspective explanatory view illustrating a mount on whichupper-stage battery modules in a first battery module group in FIG. 2are mounted, and a peripheral portion thereof;

FIG. 6 is a cross-sectional explanatory view illustrating a state wherethe battery modules in the first battery module group in FIG. 2 arearranged in two vertical stages;

FIG. 7 is a perspective explanatory view of the cooling mechanism inFIG. 2 that is seen obliquely from a rear side of the vehicle;

FIG. 8 is an enlarged perspective view illustrating arrangement of abattery module fixing section between two adjacent battery module groupsin the battery pack in FIG. 2 and of a connecting pipe below the fixingsection;

FIG. 9 is an enlarged perspective view illustrating arrangement of anexpansion valve, a flow divider, and a second junction box in thebattery pack illustrated in FIG. 2;

FIG. 10 is a plan view illustrating a state where the flow divider inFIG. 9 is arranged in an overlapping manner between a pair of batterymodules in a single-stage second battery module group when seen in avehicle width direction;

FIG. 11 is a cross-sectional explanatory view illustrating aconfiguration that the flow divider in FIG. 9 is arranged in anoverlapping manner between a first battery module and a second batterymodule in the single-stage second battery module group when seen in thevehicle width direction and that is cut along a vehicle longitudinaldirection;

FIG. 12 is a view in which arrangement of a pair of rear connectingpipes in the cooling mechanism in FIG. 3 is seen from the vehicle rearside;

FIG. 13 is a view in which the arrangement of the pair of rearconnecting pipes in the cooling mechanism in FIG. 3 is seen from avehicle lower side;

FIG. 14 is a view in which the arrangement of the pair of rearconnecting pipes in the cooling mechanism in FIG. 3 is seen obliquelydownward from the vehicle rear side;

FIG. 15 is an exploded perspective view of a single cooling pipe in thecooling mechanism in FIG. 3 and a peripheral portion thereof;

FIG. 16 is a cross-sectional explanatory view of the cooling pipe in thecooling mechanism in FIG. 3 and the peripheral portion thereof in atransverse section;

FIG. 17 is a front view of an elastic urging member in FIG. 15;

FIG. 18 is a back view of the elastic urging member in FIG. 15;

FIG. 19 is a cross-sectional view of the elastic urging member in FIG.18 that is taken along line A-A; and

FIG. 20 is a cross-sectional view of the elastic urging member in FIG.18 that is taken along line B-B.

DETAILED DESCRIPTION

A detailed description will hereinafter be made on a preferredembodiment of a vehicle battery pack according to the present disclosurewith reference to the accompanying drawings. In the following drawings,a vehicle width direction, a vehicle longitudinal direction, and avehicle vertical direction are respectively indicated by a double-headedarrow X, a double-headed arrow Y, and a double-headed arrow Z.Furthermore, a vehicle front direction is indicated by an arrow Y1.

(Overall Configuration of Electric Vehicle 1)

An electric vehicle 1 illustrated in FIG. 1 is configured to include avehicle battery pack 5 near a portion under a floor of a cabin in avehicle body 2, and the vehicle battery pack 5 includes three batterymodule groups 23, 24, 25.

More specifically, the electric vehicle 1 includes: wheels 3 that arearranged on both sides in front and rear portions of the vehicle body 2;a motor 4 that rotationally drives the two wheels 3 on the front side ofthe vehicle body 2; the battery pack 5; a power feeder 6 that reduces avoltage of power of the battery pack 5, coverts the power thereof intoAC power from DC power, and feeds the AC power to external equipment; acharger 7 that is used in a normal charging time; a quick-charging inputsection 8; a compressor 9 that is used to air-condition the cabin, thecompressor 9 being also used to cool the battery pack 5; first to thirdjunction boxes 10, 11, 12 as three electrical connection boxes; and aninverter 13 provided between the third junction box 12 and the motor 4.

Each of the first to third junction boxes 10, 11, 12 constitutes theelectrical connection box by accommodating electrical circuits,electrical components, or the like such as a relay circuit and a fuse ina case. The first junction box 10 includes an overall high-voltagesystem that is connected to all battery modules in the battery pack 5.The second junction box 11 includes a charging circuit such as aquick-charging circuit, and is directly or indirectly connected to allof the battery modules in the battery pack 5 so as to be able to chargethese battery modules. The third junction box 12 includes a vehicledrive circuit and the like. The first and third junction boxes 10, 12are connected by an electric cable C1. The first and second junctionboxes 10, 11 are connected by an electric cable C2 that runs through aclearance 28 at a center of the inside of the battery pack 5. The secondjunction box 11 is connected to the power feeder 6, the charger 7, andthe quick-charging input section 8 via cables C3 to C5, respectively.

The motor 4 is an AC motor and rotationally drives the wheels 3 on bothof the sides in the vehicle front direction Y1. A DC current that issupplied from the battery pack 5 to the inverter 13 is converted into anAC current by the inverter 13, and the motor 4 can rotate by using theAC current. Meanwhile, during deceleration of the vehicle, the ACcurrent that is generated by the motor 4 is converted into the DCcurrent by the inverter 13, and the DC current is stored in the batterymodules in the battery pack 5.

(Overall Configuration of Battery Pack 5)

As illustrated in FIG. 2, the battery pack 5 in this embodimentincludes: a lower plate 21; the three battery module groups, that is,the first to third battery module groups 23, 24, 25; an upper cover 22that covers the first to third battery module groups 23, 24, 25 fromabove; a cooling mechanism 26 that cools the first to third batterymodule groups 23, 24, 25; and a plurality of crossmembers 27, each ofwhich extends in the vehicle width direction X on an upper surface ofthe lower plate 21.

On the lower plate 21, the first to third battery module groups 23, 24,25 are sequentially aligned in the vehicle longitudinal direction Ytoward the vehicle front direction Y1.

The first battery module group 23 provided in two vertical stages isarranged in an empty space on the rearmost side of the vehicle body 2,for example, a space under a rear seat of the vehicle body 2, or thelike. That is, the first battery module group 23 includes four batterymodules, that is, a first upper-stage battery module 23 a, a secondupper-stage battery module 23 b, a first lower-stage battery module 23c, and a second lower-stage battery module 23 d.

The first upper-stage battery module 23 a is disposed above the firstlower-stage battery module 23 c in an overlapping manner with the firstlower-stage battery module 23 c in the vehicle vertical direction Z. Thesecond lower-stage battery module 23 d is disposed in alignment with thefirst lower-stage battery module 23 c in the vehicle width direction X.The second upper-stage battery module 23 b is disposed above the secondlower-stage battery module 23 d in an overlapping manner with the secondlower-stage battery module 23 d in the vehicle vertical direction Z.

The first upper-stage and second upper-stage battery modules 23 a, 23 bare attached onto a mount 39, which is illustrated in FIG. 5 and isprovided on the lower plate 21, and are thereby arranged on the firstlower-stage and second lower-stage battery modules 23 c, 23 d,respectively.

The mount 39, which is illustrated in FIG. 5, has a base 39 a and aplurality of legs 39 b, each of which extends downward from acircumferential edge of the base 39 a. A lower end portion of the leg 39b is fixed to the lower plate 21.

In addition, in this embodiment, as illustrated in FIGS. 5 to 6, thefirst upper-stage and second upper-stage battery modules 23 a, 23 b arearranged to be projected more to a vehicle rear side (an oppositedirection side from the arrow Y1) than rear ends of the firstlower-stage and second lower-stage battery modules 23 c, 23 d.

As illustrated in FIGS. 1 to 2, the second battery module group 24 isarranged on the vehicle front direction Y1 side of the first batterymodule group 23 (near an intermediate portion of the lower plate 21 inthe vehicle longitudinal direction Y). The second battery module group24 includes battery modules 24 a, 24 b provided in a single stage. Thebattery modules 24 a, 24 b are disposed in alignment in the vehiclewidth direction X.

The third battery module group 25 is arranged on the vehicle frontdirection Y1 side of the second battery module group 24, that is, theforemost side of the vehicle body 2. The third battery module group 25includes battery modules 25 a, 25 b provided in a single stage. Thebattery modules 25 a, 25 b are arranged in alignment in the vehiclewidth direction X.

(Description on Cooling Mechanism 26)

As illustrated in FIGS. 2 to 4, the cooling mechanism 26 includescooling pipes 41, each of which is provided at a position abutting alower surface of respective one of the battery modules 23 a to 23 d, 24a to 24 b, and 25 a to 25 b in the first to third battery module groups23, 24, 25, and is configured to supply a refrigerant to these coolingpipes 41 so as to cool these plural battery modules.

More specifically, the cooling mechanism 26 includes an inlet pipe 31,an expansion valve 32, a flow divider 33, a first upper cooling section34, a first lower cooling section 35, a second cooling section 36, athird cooling section 37, and an outlet pipe 38, and these are connectedin series such that the refrigerant flows sequentially. The inlet pipe31 connects between the compressor 9 (see FIG. 1) and the expansionvalve 32.

The refrigerant that is compressed by the compressor 9 is delivered tothe expansion valve 32 via the inlet pipe 31, and the expansion valve 32expands the compressed refrigerant so as to bring the refrigerant into agas-liquid mixed state. The refrigerant that is expanded by theexpansion valve 32 is delivered to the flow divider 33 through a pipe45. The flow divider 33 divides and delivers the expanded refrigerant toa pair of module cooling sections 34 a, 34 b in the first upper coolingsection 34 through a pipe 46.

The paired module cooling sections 34 a, 34 b in the first upper coolingsection 34 are arranged in alignment in the vehicle width direction Xand are each arranged on the base 39 a of the mount 39, which isillustrated in FIG. 5. The paired module cooling sections 34 a, 34 b arearranged below the first upper-stage and second upper-stage batterymodules 23 a, 23 b of the first battery module group 23 in FIG. 2, abutthe lower surfaces of these battery modules 23 a, 23 b, and individuallycool the battery modules 23 a, 23 b, respectively.

Each of the paired module cooling sections 34 a, 34 b includes: a pairof the cooling pipes 41 extending in the vehicle longitudinal directionY; and a pair of end pipes 42 extending in the vehicle width directionX.

Each of the cooling pipes 41 is a pipe in a flat plate shape and ismanufactured by using metal having superior thermal conductivity such asan aluminum alloy. The cooling pipes 41 are arranged to abut the lowersurfaces of the battery modules 23 a, 23 b. Each of a combination offront end portions and a combination of rear end portions of the pairedcooling pipes 41 is connected by the end pipe 42. Accordingly, therefrigerant that is delivered from the flow divider 33 to each of thepaired module cooling sections 34 a, 34 b sequentially flows through theend pipe 42, the pair of the cooling pipes 41, and the end pipe 42 andis next delivered to the first lower cooling section 35.

Similar to the above first upper cooling section 34, the first lowercooling section 35 includes a pair of module cooling sections 35 a, 35 baligned in the vehicle width direction X. At a position below the base39 a of the mount 39, which is illustrated in FIG. 5, each of the pairedmodule cooling sections 35 a, 35 b is arranged on the lower plate 21.The paired module cooling sections 35 a, 35 b are arranged below thefirst lower-stage and second lower-stage battery modules 23 c, 23 d ofthe first battery module group 23 in FIG. 2, abut the lower surfaces ofthese battery modules 23 c, 23 d, and individually cool the batterymodules 23 c, 23 d, respectively. Similar to the above paired modulecooling sections 34 a, 34 b, each of the paired module cooling sections35 a, 35 b includes: a pair of the cooling pipes 41 extending in thevehicle longitudinal direction Y; and a pair of the end pipes 42extending in the vehicle width direction X.

Here, as illustrated in FIGS. 12 to 14, the end pipe 42 on the vehiclerear side in the module cooling section 35 a on a lower right side inFIG. 12 is connected to the end pipe 42 in the module cooling section 34b on an upper left side in FIG. 12 via a rear coupling pipe 44 thatextends obliquely upward to the left when seen from the vehicle rearside. Similarly, the end pipe 42 on the vehicle rear side in the modulecooling section 35 b on a lower left side in FIG. 12 is connected to theend pipe 42 in the module cooling section 34 a on an upper right side inFIG. 12 via the rear coupling pipe 44 that extends obliquely upward tothe right when seen from the vehicle rear side. Accordingly, in theconfiguration illustrated in FIGS. 12 to 14, the paired rear couplingpipes 44 extend obliquely upward in a manner to cross each other.

As illustrated in FIGS. 3 to 4, the second cooling section 36 isarranged on the vehicle front direction Y1 side of the first uppercooling section 34 and the first lower cooling section 35. Similar tothe above first upper cooling section 34, the second cooling section 36includes a pair of module cooling sections 36 a, 36 b aligned in thevehicle width direction X. The pair of module cooling sections 36 a, 36b is arranged on the lower plate 21. The paired module cooling sections36 a, 36 b are arranged below the paired battery modules 24 a, 24 b ofthe second battery module group 24 in FIG. 2, abut the lower surfaces ofthese battery modules 24 a, 24 b, and individually cool the batterymodules 24 a, 24 b, respectively. Similar to the above paired modulecooling sections 34 a, 34 b, each of the paired module cooling sections36 a, 36 b includes: a pair of the cooling pipes 41 extending in thevehicle longitudinal direction Y; and a pair of the end pipes 42extending in the vehicle width direction X.

Furthermore, the third cooling section 37 is arranged on the vehiclefront direction Y1 side of the second cooling section 36, that is, theforemost side in the vehicle body 2. Similar to the above first uppercooling section 34, the third cooling section 37 includes a pair ofmodule cooling sections 37 a, 37 b aligned in the vehicle widthdirection X. The pair of module cooling sections 37 a, 37 b is arrangedon the lower plate 21. The paired module cooling sections 37 a, 37 b arearranged below the paired battery modules 25 a, 25 b of the thirdbattery module group 25 in FIG. 2, abut the lower surfaces of thesebattery modules 25 a, 25 b, and individually cool the battery modules 25a, 25 b, respectively. Similar to the above paired module coolingsections 34 a, 34 b, each of the paired module cooling sections 37 a, 37b includes: a pair of the cooling pipes 41 extending in the vehiclelongitudinal direction Y; and a pair of the end pipes 42 extending inthe vehicle width direction X.

As illustrated in FIGS. 3 to 4, two each of the three cooling sections35 to 37 that are aligned in the vehicle longitudinal direction Y on thelower plate 21 (that is, the first lower-stage, second, and thirdcooling sections 35 to 37) are coupled to each other via a connectingpipe 43 in a laterally-facing U-shape (or a U-shape).

The end pipe 42 on the vehicle front direction Y1 side in each of thepaired module cooling sections 37 a, 37 b of the third cooling section37 is connected to the outlet pipe 38. The outlet pipe 38 is connectedto a condenser, which is not illustrated, in the vehicle. Accordingly,the refrigerant that is used in the above four cooling sections 34 to 37(that is, the first upper, first lower, second, and third coolingsections 34 to 37) to cool the battery modules in the battery modulegroups 23 to 25 is delivered to and condensed by the condenser (notillustrated) via the outlet pipe 38, is compressed by the compressor 9again, and is delivered to the cooling mechanism 26 again to be used tocool the battery modules.

A flow of the refrigerant in the cooling mechanism 26, which isconfigured as described above, is a flow indicated by bold blank arrowsillustrated in FIG. 4. That is, the refrigerant is first introduced intothe pair of the module cooling sections 34 a, 34 b in the first uppercooling section 34 via the inlet pipe 31, the expansion valve 32, andthe flow divider 33. The refrigerant that is introduced into the pair ofthe module cooling sections 34 a, 34 b is then introduced into the pairof the module cooling sections 35 a, 35 b in the first lower coolingsection 35 while flow directions of the refrigerant are switched (thatis, laterally reversed) with respect to the vehicle width direction Xthrough a pair of the crossing rear coupling pipe 44. Thereafter, therefrigerant that is introduced into the pair of the module coolingsections 35 a, 35 b flows substantially linearly to the pair of themodule cooling sections 36 a, 36 b in the second cooling section 36 onthe vehicle front direction Y1 side and the pair of module coolingsections 37 a, 37 b in the third cooling section 37 via the connectingpipes 43, and finally reaches the outlet pipe 38.

A further detailed description will hereinafter be made oncharacteristics of the vehicle battery pack 5 in this embodiment.

(Description on Cooling of First Battery Module Group 23)

The vehicle battery pack 5 in this embodiment includes the first batterymodule group 23 that has the plural battery modules 23 a to 23 ddisposed in the plural stages (the two vertical stages in thisembodiment) in the mutually overlapping manner in the vehicle verticaldirection Z; and the cooling mechanism 26 that has the cooling pipes 41(first cooling pipes), each of which cools respective one of the batterymodules in the first battery module group 23, and is configured to beable to supply the refrigerant to the cooling pipes 41.

In the first battery module group 23, the plural stages of the batterymodules 23 a to 23 d only need to be disposed and are not limited to thetwo vertical stages. Three or more stages of the battery modules may bedisposed.

The cooling mechanism 26 is configured to intensify cooling of a portionbetween the battery modules 23 a, 23 c and a portion between the batterymodules 23 b, 23 d, which are adjacent to each other in the vehiclevertical direction Z, in the first battery module group 23 by thecooling pipes 41 in comparison with other portions of the battery pack5.

More specifically, the above “other portions” in this embodiment includeportions of the battery modules 24 a, 24 b in the single-stage secondbattery module group 24 (or the third battery module group 25) that arecooled by the cooling pipes 41 (second refrigerant pipes), that is, thelower surfaces of the battery modules 24 a, 24 b, and the like.

In detail, the cooling mechanism 26 is configured to supply therefrigerant to the portion between the battery modules 23 a, 23 c andthe portion between the battery modules 23 b, 23 d, which are adjacentto each other in the vehicle vertical direction Z, in the first batterymodule group 23 prior to the battery modules 24 a, 24 b in thesingle-stage second battery module group 24, so as to intensify coolingof such portions.

More specifically, the cooling pipes 41 (the first cooling pipes) in theportion between the battery modules 23 a, 23 c and the portion betweenthe battery modules 23 b, 23 d, which are adjacent to each other in thevehicle vertical direction Z, in the first battery module group 23provided in the two vertical stages (that is, the cooling pipes 41 inthe paired module cooling sections 34 a, 34 b of the first upper coolingsection 34 in FIGS. 3 to 4) are respectively connected in series withthe cooling pipes 41 (the second refrigerant pipes) for the batterymodules 24 a, 24 b in the single-stage second battery module group 24(that is, the cooling pipes 41 in the paired module cooling sections 36a, 36 b of the second cooling section 36 in FIGS. 3 to 4).

The cooling pipes 41 in the portion between the battery modules 23 a, 23c and the portion between the battery modules 23 b, 23 d, which areadjacent to each other in the vehicle vertical direction Z, are arrangedon an upstream side of the cooling pipes 41 for the battery modules 24a, 24 b in a flow direction of the refrigerant.

In the above configuration of the battery pack 5, each of the portionbetween the battery modules 23 a, 23 c and the portion between thebattery modules 23 b, 23 d, which are adjacent to each other in thevehicle vertical direction Z, in the first battery module group 23 is aportion where heat is likely to remain during use (that is, duringcharging/discharging) of the battery modules 23 a to 23 d. However, itis possible to intensify cooling (that is, improve cooling capacity) ofthese portions by the cooling pipes 41 in comparison with the otherportions of the battery pack 5. In this way, it is possible to suppressa temperature of the multi-stage first battery module group 23 frombecoming high. As a result, it is possible to prevent degradation ofcooling performance of the battery modules 23 a to 23 d, which improvesreliability.

In addition, in the above configuration of the battery pack 5, it ispossible to intensify cooling of the portion between the battery modules23 a, 23 c and the portion between the battery modules 23 b, 23 d, whichare adjacent to each other in the vehicle vertical direction Z, in thefirst battery module group 23 by the cooling pipes 41 in comparison withthe other portions, that is, the portions of the battery modules 24 a,24 b in the second battery module group 24 having the smaller number ofthe stage than the first battery module group 23 (the single stage inthis embodiment) by the second refrigerant pipes. In this way, it ispossible to suppress the temperature of the first battery module group23, which is the portion most likely to have the highest temperature inthe battery pack 5, from becoming high. In other words, it is possibleto suppress the temperature of the first battery module group 23 havingthe multi-stage battery modules 23 a to 23 d from becoming high byintensifying cooling of the portion between the upper-stage batterymodules 23 a, 23 b and the lower-stage battery modules 23 c, 23 d in thefirst battery module group 23 by the cooling pipes 41 in comparison withcooling of the single-stage battery modules 24 a, 24 b in the secondbattery module group 24 by the cooling pipes 41.

Furthermore, in the above configuration of the battery pack 5, thecooling pipes 41 (the first cooling pipes) in the portion between thebattery modules 23 a, 23 c and the portion between the battery modules23 b, 23 d, which are adjacent to each other in the vehicle verticaldirection Z, in the first battery module group 23 provided in the twovertical stages are respectively connected in series with the coolingpipes 41 (second cooling pipes) for the battery modules 24 a, 24 b ofthe single-stage second battery module group 24. In addition, thecooling pipes 41 in the portion between the battery modules 23 a, 23 cand the portion between the battery modules 23 b, 23 d, which areadjacent to each other in the vehicle vertical direction Z, are arrangedon the upstream side of the cooling pipes 41 for the battery modules 24a, 24 b in the flow direction of the refrigerant. Accordingly, thecooling mechanism 26 can supply the refrigerant, which has flowedthrough the cooling pipes 41 in the portion between the battery modules23 a, 23 c and the portion between the battery modules 23 b, 23 d thatare adjacent to each other in the vehicle vertical direction Z, to thecooling pipes 41 (the second cooling pipes) for cooling the batterymodules 24 a, 24 b in the second battery module group 24. Thus, it ispossible to suppress a temperature of each of the battery modules 23 ato 23 d in the multi-stage first battery module group 23 from becominghigh by supplying the refrigerant in a high cooling performance state tothe first battery module group 23 prior to the second battery modulegroup 24.

In the battery pack according to the present disclosure, in order tointensify cooling of the multi-stage first battery module group 23, thecooling mechanism 26 may be configured to be able to supply therefrigerant to the cooling pipes 41 for the first battery module group23 such that a refrigerant supply amount to the cooling pipes 41 (thefirst cooling pipes) for the multi-stage first battery module group 23is larger than a refrigerant supply amount to the cooling pipes 41 (thesecond cooling pipes) for the second battery module group 24 provided inthe smaller number of the stage. For example, the cooling mechanism 26may be configured to be able to adjust the refrigerant supply amount foreach of the battery module groups such that only the refrigerant supplyamount to the cooling pipes 41 for the first battery module group 23 (inparticular, the cooling pipes 41 in the portion between the batterymodules 23 a, 23 c and the portion between the battery modules 23 b, 23d, which are adjacent to each other in the vehicle vertical direction Z)is larger than the refrigerant supply amount to the cooling pipes 41 foreach of the other battery module groups 24, 25. With such aconfiguration, it is possible to supply the larger amount of therefrigerant to the battery modules 23 a to 23 d in the multi-stage firstbattery module group 23 than the amount of the refrigerant supplied tothe battery modules 24 a, 24 b in the second battery module group 24provided in the smaller number of the stage. As a result, it is possibleto suppress the temperature of each of the battery modules 23 a to 23 din the multi-stage first battery module group 23 from becoming high.

In addition, in the battery pack according to the present disclosure, inorder to intensify cooling of the multi-stage first battery module group23, it may be set that a cross-sectional area of each of the coolingpipes 41 (the first cooling pipes) for the multi-stage first batterymodule group 23 (in particular, a cross-sectional area of each of thecooling pipes 41 in the portion between the battery modules 23 a, 23 cand the portion between the battery modules 23 b, 23 d, which areadjacent to each other in the vehicle vertical direction Z) is largerthan a cross-sectional area of each of the cooling pipes 41 (the secondcooling pipes) for the second battery module group 24 provided in thesmaller number of the stage. Just as described, by increasing thecross-sectional area of each of the cooling pipes 41 for cooling thebattery modules 23 a to 23 d in the first battery module group 23 to belarger than the cross-sectional area of each of the second cooling pipesfor cooling the battery modules 24 a, 24 b in the second battery modulegroup 24, it is possible to supply the larger amount of the refrigerantto the battery modules 23 a to 23 d in the multi-stage first batterymodule group 23 than the amount of the refrigerant supplied to thebattery modules 24 a, 24 b in the second battery module group 24provided in the smaller number of the stage. As a result, it is possibleto suppress the temperature of each of the battery modules 23 a to 23 din the multi-stage first battery module group 23 from becoming high.

In the case where the cross-sectional area of each of the cooling pipes41 for the multi-stage first battery module group 23 is increased asdescribed above, the cross-sectional area of each of the cooling pipes41 for the multi-stage first battery module group 23 may be made largerthan the cross-sectional area of each of the cooling pipes 41 for thesecond battery module group 24 provided in the smaller number of thestage by increasing a width of a surface of each of the cooling pipes 41that opposes respective one of the battery modules 23 a to 23 d in anorthogonal direction to the flow direction of the refrigerant to begreater than a width of a surface of each of the cooling pipes 41 (thesecond cooling pipes) that opposes respective one of the battery modules24 a, 24 b in the second battery module group 24 provided in the smallernumber of the stage. In such a case, a cooling effect for the batterymodules in the multi-stage first battery module group 23 by the coolingpipes 41 is further improved. Thus, it is possible to further suppressthe temperature of each of the battery modules 23 a to 23 d in themulti-stage first battery module group 23 from becoming high.

(Description on Connecting Pipe 43 in Laterally-Facing U-shape)

As illustrated in above FIGS. 3 to 4, in the battery pack 5 in thisembodiment, two each of the three cooling sections 35 to 37, which arealigned in the vehicle longitudinal direction Y on the lower plate 21(that is, the first lower-stage, second, and third cooling sections 35to 37), are coupled to each other via the connecting pipe 43 in thelaterally-facing U-shape (or the U-shape). Both ends of the connectingpipe 43 couple the mutually facing end pipes 42 in respective two of thethree cooling sections 35 to 37. In this way, the connecting pipes 43communicate the cooling pipes 41 in the three cooling sections 35 to 37with each other in a manner to allow the refrigerant to flowtherethrough.

As illustrated in FIGS. 7 to 8, the connecting pipe 43 in thelaterally-facing U shape has: a pair of vehicle width direction portions43 a extending in the vehicle width direction X; and a connectingportion 43 b extending in the vehicle longitudinal direction Y in amanner to connect tips of the paired vehicle width direction portions 43a. As illustrated in FIG. 8 and FIG. 11, the connecting pipe 43 in thelaterally-facing U shape extends in the vehicle width direction X at aposition below a fixing section 30 so as to avoid interference with thefixing section 30 that fixes respective one of the battery modules inthe battery module groups 23 to 25 to the crossmember 27. In addition,in order to avoid interference with the crossmember 27, which isillustrated in FIG. 2 and FIG. 11 and extends in the vehicle widthdirection X, the connecting pipe 43 in the laterally-facing U shapeextends in the laterally-facing U shape to an outer side in the vehiclewidth direction X of end portions of the crossmember 27 while bypassingthe crossmember 27.

As described above, the battery pack 5 in this embodiment is configuredto include: the first battery module and the second battery module thatare arranged adjacent to each other (for example, the battery modules 23d, 24 b, which are illustrated in FIG. 2 and FIG. 11 and are adjacent toeach other); the first cooling pipe for cooling the first battery modulewhen being supplied with the refrigerant (for example, the cooling pipe41 that is provided in the module cooling section 35 b illustrated inFIG. 3 and abuts the lower surface of the battery module 23 dillustrated in FIG. 11); the second cooling pipe for cooling the secondbattery module when being supplied with the refrigerant (for example,the cooling pipe 41 that is provided in the module cooling section 36 billustrated in FIG. 3 and abuts the lower surface of the battery module24 b illustrated in FIG. 11); and the connecting pipe 43 thatcommunicates between the first cooling pipe and the second cooling pipein the manner to allow the refrigerant to flow therethrough, theconnecting pipe 43 connecting in the manner to allow displacement of arelative position between the first cooling pipe and the second coolingpipe.

According to this configuration, in the battery pack 5, even in the casewhere the relative position between the first cooling pipe and thesecond cooling pipe for cooling the two adjacent battery modules 23 d,24 b or the like (the cooling pipes 41 that abut the lower surfaces ofthe battery modules 23 d, 24 b, or the like) is displaced at the timewhen these first cooling pipe and second cooling pipe are assembled,during the travel of the vehicle, or the like, it is possible to allowthe displacement of the relative position between the first cooling pipeand the second cooling pipe (that is, to absorb the displacement from atarget relative position) by the connecting pipe 43. As a result, it ispossible to reduce a possibility of damage to the first cooling pipe andthe second cooling pipe due to application of bending or tensile stressto these first cooling pipe and second cooling pipe and thus is possibleto suppress the reliability of the cooling performance from beingdegraded.

The above effect by the connecting pipe 43 can be exerted by all of theconnecting pipes 43 illustrated in FIG. 3, that is, all of theconnecting pipes 43, each of which couples the two adjacent coolingpipes 41 in the vehicle longitudinal direction Y in respective two ofthe three cooling sections 35, 36, 37.

In addition, as described above, the battery pack 5 in this embodimentis configured that the first cooling pipe abuts the first battery moduleand the second cooling pipe abuts the second battery module differingfrom the first battery module. Thus, it is possible to efficiently coolthese battery modules.

The battery pack 5 in this embodiment further includes an elastic urgingmember 51 illustrated in FIGS. 15 to 16 as an urging member that urgesthe above first cooling pipe to a surface of the first battery moduleand urges the second cooling pipe to a surface of the second batterymodule. The elastic urging member 51 is disposed on a lower side of eachof the cooling pipes 41 in the module cooling sections (34 a, 34 b) to(37 a, 37 b) of the first upper, first lower, second, and third coolingsections 34 to 37 illustrated in FIGS. 3 to 4, and can urge each of thecooling pipes 41 to respective one of the lower surfaces of the batterymodules 23 a to 25 b located above the cooling pipes 41. The elasticurging member 51 is held on the lower side of the cooling pipe 41 by aholder (a holding member) 52 illustrated in FIGS. 15 to 16. In thisconfiguration, the elastic urging members 51 respectively urge the firstcooling pipe and the second cooling pipe to the surfaces of the firstbattery module and the second battery module. In this way, the firstcooling pipe and the second cooling pipe can reliably abut the surfacesof the first battery module and the second battery module, respectively.As a result, it is possible to further efficiently cool these batterymodules.

In the battery pack 5 of this embodiment, the first cooling pipe isarranged at a position located between the lower surface of the firstbattery module and the elastic urging member 51. The second cooling pipeis arranged at a position located between the lower surface of thesecond battery module and the elastic urging member 51. The elasticurging members 51 urge the first cooling pipe to the lower surface ofthe first battery module and urge the second cooling pipe to the lowersurface of the second battery module. In this configuration, the firstcooling pipe and the second cooling pipe are interposed betweenrespective one of the lower surfaces of the two different first andsecond battery modules and the elastic urging member 51, and thus arestructured that the relative position between the first cooling pipe andthe second cooling pipe is likely to be displaced. Even with such astructure, it is possible to suppress the bending or tensile stress frombeing applied to the first cooling pipe and the second cooling pipe byallowing the displacement of the relative position between the firstcooling pipe and the second cooling pipe by the connecting pipes 43.

As illustrated in FIG. 8 and FIG. 11, the battery pack 5 in thisembodiment includes the fixing section 30 that fixes respective one ofthe first battery module and the second battery module (for example, acombination of the adjacent battery modules 23 d, 24 b, a combination ofthe adjacent battery modules 24 b, 25 b, or the like illustrated in FIG.2 and FIG. 11) to the crossmember 27 as a base portion of the batterypack 5. The fixing section 30 is an L-shaped bracket or the like. Thefixing section 30 is arranged between the first battery module and thesecond battery module described above. The connecting pipe 43 in thelaterally-facing U shape is arranged to separate downward from thefixing section 30 in a manner to avoid the fixing section 30. In thisconfiguration, it is possible to avoid the interference between theconnecting pipe 43 and the fixing section 30.

In addition, as illustrated in FIG. 8 and FIG. 11, in the battery pack 5of this embodiment, the first battery module corresponding to the firstcooling pipe (for example, the battery module 23 d in FIG. 11) and thesecond battery module corresponding to the second cooling pipe (forexample, the battery module 24 b in FIG. 11) are each fixed to thecrossmember 27 as the base portion by the different fixing section 30.In this configuration, the first battery module and the second batterymodule are each fixed to the crossmember 27 as the base portion by thedifferent fixing section 30. Thus, it is structured that an attachmenterror is likely to occur between the first cooling pipe on the firstbattery module side and the second cooling pipe on the second batterymodule side. However, since the displacement of the relative positionbetween the first cooling pipe and the second cooling pipe is allowed bythe connecting pipe 43, it is possible to suppress the bending ortensile stress from being applied to the first cooling pipe K and thesecond cooling pipe.

Furthermore, in the battery pack 5 of this embodiment, the connectingpipe 43 has portions (the vehicle width direction portions 43 a in FIG.7), each of which extends in a different direction from a direction (thevehicle longitudinal direction Y in FIG. 7) in which a straight lineconnecting the first cooling pipe (for example, the cooling pipe 41 inthe second cooling section 36 illustrated in FIG. 7) and the secondcooling pipe (for example, the cooling pipe 41 in the third coolingsection 37 illustrated in FIG. 7) by the shortest distance. Accordingly,the connecting pipe 43 is easily deformed, and it is thus possible toreliably allow the displacement of the relative position between thefirst cooling pipe and the second cooling pipe by the connecting pipe43.

The base portion of the battery pack 5 in this embodiment has thecrossmembers 27, each of which extends in the vehicle width direction X(see FIG. 2 and FIG. 11). The connecting pipe 43 has portions (thevehicle width direction portions 43 a in FIG. 7), each of which extendsin the vehicle width direction X in the manner to bypass the crossmember27. Accordingly, the connecting pipe 43 is easily deformed while theinterference between the connecting pipe 43 and the crossmember 27 isavoided. As a result, it is possible to reliably allow the displacementof the relative position between the first cooling pipe (for example,the cooling pipe 41 in the second cooling section 36 illustrated in FIG.7) and the second cooling pipe (for example, the cooling pipe 41 in thethird cooling section 37 illustrated in FIG. 7) by the connecting pipe43. In particular, in this configuration, the connecting pipe 43 has thevehicle width direction portions 43 a, each of which extends in thevehicle width direction X. Thus, in particular, the connecting pipe 43is easily deformed in the vehicle longitudinal direction Y and thevertical direction Z, and thus can reliably allow the displacement ofthe relative position between the first cooling pipe and the secondcooling pipe in these directions Y and Z.

In addition, as illustrated in FIG. 7, the vehicle width directionportions 43 a, each of which extends in the vehicle width direction X inthe manner to bypass the crossmember 27, in the connecting pipe 43extend in a horizontal direction, and the first and second cooling pipes(for example, the cooling pipes 41 in the second to third coolingsections 36, 37) also extend in the horizontal direction. Thus, even inthe case where the relative position between the first cooling pipe andthe second cooling pipe is displaced vertically, it is possible toabsorb such displacement by the deformation of the connecting pipe.

(Description on Expansion Valve 32)

The battery pack 5 in this embodiment includes: the first battery modulegroup 23 (see FIG. 2) that has the plural battery modules disposed inthe plural stages in the overlapping manner in the vehicle verticaldirection Z; the cooling pipes 41 (the cooling pipes 41 in the firstupper and lower cooling sections 34 in FIG. 3) for cooling the pluralbattery modules 23 a to 23 d of the first battery module group 23 whenbeing supplied with the refrigerant; and the expansion valve 32 (seeFIG. 3) that is arranged on the upstream side of the cooling pipes 41 inthe flow direction of the refrigerant, expands the refrigerantcompressed by the compressor 9 (see FIG. 1), and supplies therefrigerant to the cooling pipes 41. As illustrated in FIG. 9, theexpansion valve 32 is arranged at a position that is adjacent to thefirst battery module group 23 (a lateral position that is adjacent tothe first battery module group 23 in the vehicle width direction X inFIG. 9).

In this configuration, since the expansion valve 32 is arranged at theposition adjacent to the multi-stage first battery module group 23, therefrigerant in the high cooling performance state immediately afterbeing expanded by the expansion valve 32 can be supplied to the firstbattery module group 23. Thus, it is possible to improve coolingperformance for the first battery module group 23.

In addition, in the battery pack 5 of this embodiment, the expansionvalve 32 is arranged at the position adjacent to the first batterymodule group 23 in the vehicle width direction X. With thisconfiguration, the position that is adjacent to the first battery modulegroup 23 in the vehicle width direction X, that is, an empty space onthe lateral side of the first battery module group 23 can be usedeffectively. Thus, it is possible to suppress enlargement of the batterypack 5.

The vehicle battery pack 5 is arranged in a space having a smallvertical distance under the floor of the cabin of the vehicle body 2.Thus, a restriction is imposed on a vertical width of the vehiclebattery pack 5. Accordingly, there is a circumstance that it isdifficult to arrange the expansion valve 32 above or below the firstbattery module group 23. When such technical background is concerned,the expansion valve 32 is arranged at the adjacent position, where asufficient space is available, to the first battery module group 23 inthe vehicle width direction X. In this way, it is possible to suppressthe enlargement of the vehicle battery pack 5, particularly, in thevertical direction, which is extremely effective in terms of a vehiclelayout.

Furthermore, in the battery pack 5 of this embodiment, the expansionvalve 32 is connected to the cooling pipes 41, and the end pipes 42,which are arranged on the front side of the battery modules 23 a, 23 billustrated in FIG. 9, are provided as front surface side pipes, each ofwhich is arranged to extend in the vehicle width direction X along afront surface of the first battery module group 23 facing the vehiclefront direction Y1. In this configuration, the refrigerant in the highcooling performance state immediately after being expanded by theexpansion valve 32 flows through the front surface side pipes (the endpipes 42 illustrated in FIG. 9). In this way, it is possible to cool thefirst battery module group 23 from the front surface. It is alsopossible to cool the battery modules 24 a, 24 b of the single-stagesecond battery module group 24 on the vehicle front direction Y1 side ofthe front surface side pipes (the end pipes 42 illustrated in FIG. 9) bythe front surface side pipes.

As illustrated in FIG. 9, the battery pack 5 in this embodiment furtherincludes the second junction box 11 as the electrical connection boxthat is electrically connected to the first battery module group 23.

The second junction box 11 is arranged at a position adjacent to theexpansion valve 32. For example, the second junction box 11 is arrangedat the adjacent position in any of front, rear, and upper directions ofthe expansion valve 32. In such a configuration that the second junctionbox 11 is arranged at the position adjacent to the expansion valve 32,air around the expansion valve 32 is cooled in conjunction with theexpansion of the refrigerant by the expansion valve 32, and the secondjunction box 11 can be cooled by using the cooled air. As a result, itis possible to suppress a temperature of the second junction box 11 frombecoming high.

Moreover, in the battery pack 5 of this embodiment, as the compressorthat compresses the refrigerant to be used in the cooling mechanism 26,the compressor 9 for air-conditioning the inside of the cabin of thevehicle body 2 is used. Accordingly, it is possible to compress therefrigerant for cooling the first battery module group 23 and the othersecond to third battery module groups 24, 25 by using the compressor 9for air-conditioning the inside of the cabin. As a result, the singlecompressor 9 can have two applications of air-conditioning and coolingthe battery modules, and thus manufacturing cost of the vehicle can bereduced.

(Description on Flow Divider 33)

As illustrated in FIGS. 9 to 11, in the battery pack 5 of thisembodiment, the flow divider 33 is arranged between the paired batterymodules 24 a, 24 b (the first battery module and the second batterymodule), which are arranged in alignment in the vehicle width directionX as a specified arrangement direction, in the second battery modulegroup 24. The above “specified arrangement direction” is not limited tothe vehicle width direction X and may be the vehicle longitudinaldirection Y.

As illustrated in FIGS. 3 to 4, the flow divider 33 as described abovedelivers the refrigerant in an expanded state that is supplied from theexpansion valve 32 through the pipe 46 in a manner to divide therefrigerant to each of the cooling pipes 41 of the paired module coolingsections 34 a, 34 b in the first upper cooling section 34. Therefrigerant that is divided and delivered to the first upper coolingsection 34 is sequentially delivered to each of the cooling pipes 41 inthe first lower cooling section 35, the second cooling section 36, andthe third cooling section 37 that are arranged on the downstream side inthe flow direction of the refrigerant while the two flows of therefrigerant that are divided and delivered are kept. As a result, theflow divider 33 can divide and supply a liquid medium to the coolingpipes 41 (the first and second cooling pipes) in the second coolingsection 36 that cools the paired battery modules 24 a, 24 b (the firstbattery module and the second battery module) located on both sides ofthe flow divider 33.

According to the above configuration, the flow divider 33 is arrangedbetween the paired battery modules 24 a, 24 b (the first battery moduleand the second battery module) that are arranged in alignment in thespecified arrangement direction (the vehicle width direction X). Thus,it is possible to improve distributivity of the refrigerant to thepaired battery modules 24 a, 24 b (the first battery module and thesecond battery module) (that is, uniformity of the refrigerant supplyamount to each of the battery modules 23 a to 25 b).

In addition, it is possible to improve the distributivity of therefrigerant to each of combinations of the other paired battery modulesillustrated in FIG. 2, that is, the combination of the battery modules23 a, 23 b, the combination of the battery modules 23 c, 23 d, and thecombination of the battery modules 25 a, 25 b.

As illustrated in FIG. 2, in the battery pack 5 of this embodiment, thepaired battery modules 24 a, 24 b (the first battery module and thesecond battery module) constitute the single-stage second battery modulegroup 24 in which the battery modules are disposed in the single stagein the vehicle vertical direction Z. In addition to the single-stagesecond battery module group 24, the battery pack 5 includes themulti-stage first battery module group 23 in which the battery modulesare disposed in the plural stages in the vehicle vertical direction Z.The single-stage second battery module group 24 and the multi-stagefirst battery module group 23 are arranged adjacent to each other in adifferent direction (the vehicle longitudinal direction Y) from thespecified arrangement direction (the vehicle width direction X). Asillustrated in FIGS. 9 to 11, the flow divider 33 in this embodiment isarranged between the paired battery modules 24 a, 24 b in thesingle-stage second battery module group 24.

According to this configuration, even in the case where it is configuredthat the single-stage second battery module group 24 and the multi-stagefirst battery module group 23 are arranged adjacent to each other in thedifferent direction (the vehicle longitudinal direction Y) from thespecified arrangement direction (the vehicle width direction X), theflow divider 33 is arranged between the paired battery modules 24 a, 24b in the single-stage battery module group 24, and thus it is possibleto suppress a projection amount of the flow divider 33 from thesingle-stage second battery module group 24 in the vehicle verticaldirection Z. As a result, it is possible to suppress an increase in adimension (that is, a height) of the vehicle battery pack 5 in thevehicle vertical direction Z.

In the battery pack 5 of this embodiment, the flow divider 33 isarranged in a manner to overlap the single-stage second battery modulegroup 24 when seen in the arrangement direction (when seen in thevehicle width direction X in this embodiment). As a result, it ispossible to suppress an increase in a dimension (that is, a height) ofthe vehicle battery pack 5 in the vehicle vertical direction Z.

In the battery pack 5 of this embodiment, the above the specifiedarrangement direction is preferably the vehicle width direction X. Insuch a case, the paired battery modules 24 a, 24 b (the first batterymodule and the second battery module) are arranged in alignment in thevehicle width direction X, and the flow divider 33 is arrangedtherebetween. Thus, it is possible to improve the distributivity of therefrigerant to the paired battery modules 24 a, 24 b.

In addition, in the case where the flow divider 33 is arranged in themanner to overlap the single-stage battery module group 24 when seen inthe vehicle width direction X, it is possible to suppress the increasein each of the dimensions of the vehicle battery pack 5 in the vehiclevertical direction Z and the vehicle longitudinal direction Y.

In the battery pack 5 of this embodiment, the expansion valve 32 thatsupplies the refrigerant to the flow divider 33 is preferably arrangedon the outer side of any of the paired battery modules 24 a, 24 b (thefirst battery module and the second battery module) in the vehicle widthdirection X. With this configuration, it is possible to supply therefrigerant in the high cooling performance state immediately afterbeing discharged from the expansion valve 32 to the flow divider 33 anddivide the refrigerant from the flow divider 33 into the paired batterymodules 24 a, 24 b (the first battery module and the second batterymodule) and each of the combinations of the other paired battery modulesillustrated in FIG. 2, that is, the combination of the battery modules23 a, 23 b, the combination of the battery modules 23 c, 23 d, and thecombination of the battery modules 25 a, 25 b. In addition, the positionthat is adjacent to the first battery module group 23 or the secondbattery module group 24 in the vehicle width direction X, that is, theempty space on the lateral side of the first battery module group 23 orthe second battery module group 24 can be used effectively for theexpansion valve 32. Thus, it is possible to suppress the enlargement ofthe vehicle battery pack 5.

As illustrated in FIGS. 1 to 2 and FIGS. 9 to 11, in the battery pack 5of this embodiment, a clearance 28 having such a width that the cable C2(the electric cable) in the vehicle battery pack 5 can be arranged isformed between the paired battery modules 24 a, 24 b (the first batterymodule and the second battery module) and the other paired batterymodules 25 a, 25 b. The flow divider 33 is arranged in the clearance 28.With this configuration, not only the flow divider 33 but also the cableC2 can be arranged in the clearance 28 between the paired batterymodules 24 a, 24 b. Thus, it is possible to effectively use a space ofthe clearance 28 between the paired battery modules 24 a, 24 b and thusto downsize the entire vehicle battery pack 5.

(Description on Pair of Rear Coupling Pipes 44)

As illustrated in FIG. 2, in the battery pack 5 of this embodiment, thefirst battery module group 23 includes the four battery modules, thatis, the first lower-stage battery module 23 c, the first upper-stagebattery module 23 a that is disposed in the overlapping manner with thefirst lower-stage battery module 23 c in the vehicle vertical directionZ, the second lower-stage battery module 23 d that is disposed inalignment with the first lower-stage battery module 23 c in the vehiclewidth direction X, and the second upper-stage battery module 23 b thatis disposed in the overlapping manner with the second lower-stagebattery module 23 d in the vehicle vertical direction Z.

As illustrated in FIGS. 3 to 4, in order to cool the four batterymodules 23 a to 23 d of the above first battery module group 23, thecooling mechanism 26 includes the pair of the module cooling sections 34a, 34 b of the first upper cooling section 34 and the pair of the modulecooling sections 35 a, 35 b of the first lower cooling section 35. Eachof the module cooling sections 34 a, 34 b, 35 a, 35 b includes thecooling pipes 41 that abut the lower surface of respective one of thebattery modules 23 a to 23 d for cooling. The cooling pipes 41 in eachof the module cooling sections 34 a, 34 b, 35 a, 35 b are connected tothe end pipe 42 on the vehicle rear side.

As described above, as illustrated in FIGS. 12 to 14, in the batterypack 5 of this embodiment, the paired rear coupling pipes 44 extendobliquely upward in the manner to cross each other. More specifically,as illustrated in FIGS. 12 to 14, the end pipe 42 on the vehicle rearside of the module cooling section 35 a (on the lower right side in FIG.12) for cooling the first lower-stage battery module 23 c (see FIG. 2)is connected to the end pipe 42 of the module cooling section 34 b (onthe upper left side in FIG. 12) for cooling the second upper-stagebattery module 23 b via the rear coupling pipe 44 (a first connectingpipe) that extends obliquely upward to the left when seen from thevehicle rear side. Similarly, the end pipe 42 on the vehicle rear sideof the module cooling section 35 b (on the lower left side in FIG. 12)for cooling the second lower-stage battery module 23 d is connected tothe end pipe 42 of the module cooling section 34 a (on the upper rightside in FIG. 12) for cooling the first upper-stage battery module 23 avia the rear coupling pipe 44 (a second connecting pipe) that extendsobliquely upward to the right when seen from the vehicle rear side.

In other words, one (the first connecting pipe) of the rear couplingpipes 44 illustrated in FIGS. 12 to 14 connects the cooling pipes 41 forthe first lower-stage battery module 23 c (the cooling pipes 41 on themodule cooling section 35 a side in FIGS. 3 to 4) and the cooling pipes41 for the second upper-stage battery module 23 b (those on the modulecooling section 34 b side). Meanwhile, the other (the second connectingpipe) of the rear coupling pipes 44 connects the cooling pipes 41 forthe first upper-stage battery module 23 a (those on the module coolingsection 34 a side) and the cooling pipes 41 for the second lower-stagebattery module 23 d (those on the module cooling section 35 b side).

With this configuration, it is possible to allow the displacement of therelative position of the cooling pipes 41 for cooling each of the abovefour battery modules 23 a to 23 d by respective one of the paired rearcoupling pipes 44 (the first connecting pipe and the second connectingpipe). As a result, it is possible to suppress the application of thebending or tensile stress to each of the cooling pipes 41 and therebysuppress the reliability of the cooling performance of the vehiclebattery pack 5 from being degraded.

In addition, in the battery pack 5 of this embodiment, the paired rearcoupling pipes 44 (the first connecting pipe and the second connectingpipe) are arranged to overlap in a plan view (for example, see a backview in FIG. 13). In this way, it is possible to suppress theenlargement of the vehicle battery pack 5 in the longitudinal directionthereof (that is, the vehicle longitudinal direction Y).

Furthermore, in the battery pack 5 of this embodiment, each of thepaired rear coupling pipes 44 (the first connecting pipe and the secondconnecting pipe) is at least partially formed of anelastically-deformable hose 44 a (see FIG. 12). The hose 44 a only needsto be an elastically-deformable tubular member and is, for example, apipe that is made of a resin or metal such as copper. In theconfiguration of the rear coupling pipes 44, each of which has this hose44 a, compared to a case where each of the paired rear coupling pipes 44is entirely manufactured by the metal pipe, it is possible to allowdisplacement of the relative position by the hoses 44 a that canelastically be deformed in a small space.

More specifically, as illustrated in FIG. 12, in the battery pack 5 ofthis embodiment, the paired rear coupling pipes 44 (the first connectingpipe and the second connecting pipe) each include: theelastically-deformable hose 44 a; metal pipes 44 b; coupling sections 44c, each of which couples the hose 44 a and the metal pipe 44 b; and acoupling section protector 44 d that covers one of the coupling sections44 c. For example, each of the coupling sections 44 c is a metalliccaulking section or the like.

For example, the coupling section protector 44 d is a cylindrical memberthat is manufactured by a softer material such as the resin than themetal. In FIG. 12, the coupling section protector 44 d is provided toany one coupling section 44 c of the two vertically-aligned couplingsections 44 c, which are adjacent to each other, among the four couplingsections 44 c but may be provided to all of the coupling sections 44 c.

In this configuration, between the paired rear coupling pipes 44 (thefirst connecting pipe and the second connecting pipe), interferencebetween the coupling sections 44 c, each of which couples the hose 44 aand the metal pipe 44 b, can be prevented by the coupling sectionprotectors 44 d.

In addition, in the battery pack 5 of this embodiment, each of thepaired rear coupling pipes 44 (the first connecting pipe and the secondconnecting pipe) includes a hose protector 44 e that covers the hose 44a. In this way, between the paired rear coupling pipes 44 (the firstconnecting pipe and the second connecting pipe), interference betweenthe hoses 44 a can be prevented by the hose protectors 44 e.

It is also possible to prevent interference between each of the hoses 44a and the mount 39 (particularly, the base 39 a) (see FIG. 14) by thehose protector 44 e. In addition, as illustrated in FIG. 6 and FIG. 14,each of the battery modules 23 a, 23 b is fixed to an end portion on thevehicle rear side of the mount 39 via a bracket 40. However, it is alsopossible to prevent interference between the hose 44 a and the bracket40 by the above hose protector 44 e.

In the battery pack 5 of this embodiment, the paired rear coupling pipes44 (the first connecting pipe and the second connecting pipe) arearranged in the manner to cross each other (in a so-called cross-coupledfashion). As a result, compared to a case where the paired rear couplingpipes 44 are arranged in a manner not to cross each other, it ispossible to reduce a length of each of the paired rear coupling pipes44.

In other words, in the configuration illustrated in FIGS. 12 to 14, thepaired rear coupling pipes 44 extend obliquely upward in the manner tocross each other. Thus, compared to a case where each of the paired rearcoupling pipes 44 simply extends in the vehicle vertical direction Z, itis possible to secure the long pipe length.

As illustrated in FIG. 2, FIG. 6, and FIG. 14, in the battery pack 5 ofthis embodiment, the first upper-stage battery module 23 a and thesecond upper-stage battery module 23 b are arranged to be respectivelyprojected more to the rear of the vehicle (in the opposite directionfrom the arrow Y1 indicative of the vehicle front direction) than thefirst lower-stage battery module 23 c and the second lower-stage batterymodule 23 d, so as to be each formed with a projected portion 49 (seeFIG. 6 and FIG. 14). As illustrated in FIG. 6 and FIG. 14, the pairedrear coupling pipes 44 (the first connecting pipe and the secondconnecting pipe) are arranged below the projected portions 49 of thefirst upper-stage and second upper-stage battery modules 23 a, 23 b. Asa result, the paired rear coupling pipes 44 are protected by theprojected portions 49 of the first upper-stage and second upper-stagebattery modules 23 a, 23 b. Thus, it is possible to prevent damage tothe paired rear coupling pipes 44 by a collision of another vehicle orthe like from the vehicle rear side.

In the above embodiment, the pair of the coupling pipes 44 is providedon the vehicle rear side of the battery modules 23 a to 23 d. However,the present disclosure is not limited thereto, and the pair of thecoupling pipes 44 may be provided on a vehicle front side.

(Description on Elastic Urging Member 51)

As illustrated in FIG. 3, in the battery pack 5 of this embodiment, thecooling mechanism 26 includes the elastic urging member 51, which urgesthe cooling pipe 41 in a direction (upward) to make the cooling pipe 41abut the surface (the lower surface in this embodiment) of the batterymodule (respective one of the battery modules 23 a to 25 b in FIG. 2),for each of the cooling pipes 41 in the flat plate shapes.

As illustrated in FIG. 15, one or a plurality of the elastic urgingmembers 51 is provided to the single cooling pipe 41. In the exampleillustrated in FIG. 15, the elastic urging member 51 that is dividedinto three pieces to facilitate manufacturing by using an existingshaping mold is provided on a lower surface of the single cooling pipe41.

As illustrated in FIGS. 15 to 16, the elastic urging member 51 is heldon the lower surface of the cooling pipe 41 in the flat plate shape viathe holder 52 formed of the resin or the like. In addition, in thisembodiment, a heater 53 is also held on the lower surface of the coolingpipe 41 by the holder 52. The heater 53 is used to heat respective oneof the battery modules 23 a to 25 b to a specified use conditiontemperature during driving in a cold region, and the like. The heater 53can heat the battery module via the cooling pipe 41. The cooling pipe 41in the flat plate shape only needs to be formed with a channel, throughwhich the refrigerant can flow, therein. As illustrated in FIG. 16, thechannel may be divided into a plurality of channels.

As illustrated in FIG. 6 and FIGS. 15 to 20, the elastic urging member51 includes a plurality of elastically-deformable legs 51 a that arealigned in the longitudinal direction of the cooling pipe 41. Morespecifically, the elastic urging member 51 is an elastically-deformablemember that is manufactured by using rubber or the like and includes, asillustrated in FIGS. 17 to 18, the plurality (four in FIGS. 17 to 18) oflegs 51 a and a base 51 b that couples root-side end portions at upperends of these plural legs 51 a. The plurality of the legs 51 a and thebase 51 b are integrally molded of an elastically-deformable resin.

Each of the legs 51 a has a tapered shape overall and, specifically, hasa substantially trapezoidal flat plate shape illustrated in FIG. 20. Inaddition, as illustrated in FIG. 17 and FIG. 19, a tip of the leg 51 ais rounded and has a curved surface shape. Furthermore, the leg 51 a ismolded of the elastically-deformable resin and, as illustrated in FIGS.19 to 20, has a hollow shape.

The plurality of the legs 51 a of the elastic urging member 51 canindividually abut an abutment surface of a case for the battery pack 5or the like (for example, the lower plate 21 in FIG. 2, an upper surfaceof the mount 39 in FIG. 5, or the like).

In the battery pack 5 of this embodiment, as described above, each ofthe cooling pipes 41 in the flat plate shapes includes the elasticurging member 51 that urges the cooling pipe 41 in the direction to abutthe surface of the battery module. Since this elastic urging member 51has the plurality of the elastically-deformable legs 51 a that arealigned in the longitudinal direction of the cooling pipe 41, it ispossible to urge the cooling pipe 41 to the surface of the batterymodule by each of the legs 51 a. In this way, it is possible to suppressa variation in an urging force received by the cooling pipe 41 between ahigh-temperature time and a low-temperature time. As a result, in astate of receiving the urging force, the variation in which issuppressed (that is, a state where a variation in thermal contactresistance is suppressed), the cooling pipe 41 abuts the surface of thebattery module, and a variation in the cooling performance for thebattery module by the cooling pipe 41 is thereby suppressed.

In addition, in the battery pack 5 of this embodiment, the cooling pipe41 can be urged to the lower surface of respective one of the batterymodules 23 a to 25 b by the individual legs 51 a of the elastic urgingmember 51. In this configuration, the battery module is placed on thecooling pipe 41, and thus the elastic urging member 51 can receiveweight of the battery module via the cooling pipe 41. As a result, theelastic urging member 51 is elastically deformed by using the weight ofthe battery module and can urge the cooling pipe 41 to the lower surfaceof the battery module by using a restoring force of the elastic urgingmember 51. Thus, with a simple structure that the battery module, thecooling pipe 41, and the elastic urging member 51 are stacked andarranged in the vehicle vertical direction Z, the variation in theurging force received by the cooling pipe 41 is suppressed, and thevariation in the cooling performance for respective one of the batterymodules 23 a to 25 b by the cooling pipe 41 is suppressed.

In the above embodiment, the description has been made on the example inwhich the elastic urging member 51 urges the cooling pipe 41 upward suchthat the cooling pipe 41 abuts the lower surface of respective one ofthe battery modules 23 a to 25 b. However, the present disclosure is notlimited thereto. As a modified example, the elastic urging member 51 mayurge the cooling pipe 41 laterally such that the cooling pipe 41 abuts asurface other than the lower surface of respective one of the batterymodules 23 a to 25 b, for example, a lateral surface of the batterymodule.

In the battery pack 5 of this embodiment, since the tip of the leg 51 ahas the curved surface shape, the leg 51 a can smoothly and elasticallybe deformed when the leg 51 a abuts the abutment surface of the case forthe battery pack 5, or the like (for example, the lower plate 21 in FIG.2, the upper surface of the mount 39 in FIG. 5, or the like). As aresult, an impact of a variation in a tip shape of the legs 51 a becomessmall, and thus the cooling pipe 41 can reliably be urged to respectiveone of the battery modules 23 a to 25 d.

In the battery pack 5 of this embodiment, since the leg 51 a has thehollow shape, the leg 51 a can smoothly and easily be deformedelastically when the leg 51 a abuts the abutment surface of the case forthe battery pack or the like (for example, the lower plate 21 in FIG. 2,the upper surface of the mount 39 in FIG. 5, or the like). As a result,even in the case where an attachment error of the cooling pipe 41 orrespective one of the battery modules 23 a to 25 b 25 b occurs, such anerror can reliably be absorbed by the elastic deformation of the leg 51a, and thus the cooling pipe 41 can further reliably be urged torespective one of the battery modules 23 a to 25 b.

In the battery pack 5 of this embodiment, since the leg 51 a has thetapered shape, the leg 51 a can smoothly and elastically be deformedwhen the leg 51 a abuts the abutment surface of the case for the batterypack or the like (for example, the lower plate 21 in FIG. 2, the uppersurface of the mount 39 in FIG. 5, or the like). As a result, the impactof the variation in the tip shape of the legs 51 a becomes small, andthus the cooling pipe 41 can reliably be urged to the battery module.

As illustrated in FIG. 15, in the battery pack 5 of this embodiment,since the elastic urging member 51 is configured to be divided into theplural (four in FIG. 15) pieces, it is possible to improve productivityof the elastic urging member 51. More specifically, the elastic urgingmember 51 can be molded by using the existing shaping mold, and thus themanufacturing cost can be reduced.

As illustrated in FIG. 6, in the battery pack 5 of this embodiment, eachof the battery modules 23 a to 25 d has plural sheets of battery cells29. In addition, it is designed that the number of the legs 51 a of theelastic urging member 51 is the same as the number of the battery cells29. Furthermore, the plural legs 51 a are arranged in alignment in analignment direction of the plural battery cells 29 (the vehiclelongitudinal direction Yin FIG. 6). Each of the legs 51 a is arranged ata position capable of applying the upward urging force to respective oneof the battery cells 29. In this configuration, the plural legs 51 a ofthe elastic urging member 51 can apply the uniform urging force to theplural sheets of the battery cells 29 in each of the battery modules 23a to 25 b. Accordingly, there is no case where the excessive urgingforce is applied to the certain battery cell 29, and thus a possibilitythat only such a battery cell 29 individually moves upward to damage anelectrical connection section, such as a bus bar, between the batterycells is reduced.

As illustrated in FIGS. 15 to 16, the battery pack 5 in this embodimentincludes the holder 52 as the holding member that is arranged betweenthe cooling pipe 41 and the elastic urging member 51 and holds theelastic urging member 51 on the cooling pipe 41. In this configuration,since the holder 52 (the holding member) holds the cooling pipe 41 atthe position between the cooling pipe 41 and the elastic urging member51, a holding property for the cooling pipe 41 can be improved. As aresult, the elastic urging members 51 apply the uniform urging force tothe cooling pipes 41, and thus the battery modules 23 a to 25 b can becooled evenly by the cooling pipes 41.

As illustrated in FIGS. 15 to 16, the battery pack 5 in this embodimentincludes the heater 53 that heats respective one of the battery modules23 a to 25 b. The holder 52 (the holding member) holds the heater 53 ata position capable of heating respective one of the battery modules 23 ato 25 b. In this configuration, since the holder 52 (the holding member)holds the heater 53 at the position capable of heating respective one ofthe battery modules 23 a to 25 b, it is possible to reliably heat thebattery modules 23 a to 25 b evenly.

The elastic urging member 51 may be made of the resin or the metalinstead of the rubber as described above as long as the elastic urgingmember 51 is configured to be able to urge the cooling pipe 41 torespective one of the battery modules 23 a to 25 b.

What is claimed is:
 1. A vehicle battery pack comprising: a batterymodule; a cooling pipe in a flat plate shape that abuts a surface of thebattery module; and an urging member configured to urge the cooling pipein a direction to abut the surface of the battery module, the urgingmember has plural elastically-deformable legs that are aligned in alongitudinal direction of the cooling pipe.
 2. The vehicle battery packaccording to claim 1, wherein the surface of the battery module is alower surface of the battery module.
 3. The vehicle battery packaccording to claim 1, wherein a tip of each of the legs has a curvedsurface shape.
 4. The vehicle battery pack according to claim 1, whereineach of the legs has a hollow shape.
 5. The vehicle battery packaccording to claim 1, wherein each of the legs has a tapered shape. 6.The vehicle battery pack according to claim 1, wherein the urging membercomprises plural pieces.
 7. The vehicle battery pack according to claim1, wherein the battery module has plural sheets of battery cells, anumber of the legs is the same as a number of the battery cells, theplural legs are arranged in alignment in an alignment direction of theplural sheets of the battery cells, and each of the legs is arranged ata position configured to apply an urging force to respective one of thebattery cells.
 8. The vehicle battery pack according to claim 1, furthercomprising: a holding member that is arranged between the cooling pipeand the urging member and is configured to hold the urging member on thecooling pipe.
 9. The vehicle battery pack according to claim 1, furthercomprising: a heater configured to heat the battery module, wherein theholding member is configured to hold the heater at a position capable ofheating the battery module.
 10. The vehicle battery pack according toclaim 2, wherein a tip of each of the legs has a curved surface shape.11. The vehicle battery pack according to claim 2, wherein each of thelegs has a hollow shape.
 12. The vehicle battery pack according to claim2, wherein each of the legs has a tapered shape.
 13. The vehicle batterypack according to claim 10, wherein each of the legs has a hollow shape.14. The vehicle battery pack according to claim 10, wherein each of thelegs has a tapered shape.
 15. The vehicle battery pack according toclaim 4, wherein the urging member comprises plural pieces.
 16. Thevehicle battery pack according to claim 14, wherein the battery modulehas plural sheets of battery cells, a number of the legs is the same asa number of the battery cells, the plural legs are arranged in alignmentin an alignment direction of the plural sheets of the battery cells, andeach of the legs is arranged at a position configured to apply an urgingforce to respective one of the battery cells.
 17. The vehicle batterypack according to claim 14, further comprising: a holding member that isarranged between the cooling pipe and the urging member and isconfigured to hold the urging member on the cooling pipe.
 18. Thevehicle battery pack according to claim 14, further comprising: a heaterconfigured to heat the battery module, wherein the holding member isconfigured to hold the heater at a position capable of heating thebattery module.